Hematopoietic stem cells (HSCs), which have the ability to differentiate into various types of blood cell lines, are usually separate from the bone marrow. But these cells are also present in a small amount in the peripheral blood, and their amounts increase in blood following injection of G-CSF. However, the mechanism involved in moving HSCs under the influence of G-CSF is unknown. The aim of this study was to investigate the role of circadian rhythms and nervous system in HSCs mobilization. Despite the abandant information on the effect of 24-hour rhythms in physiological processes in the body, there is no evidence of the role of circadian rhythms and its relation to the nervous system receiving environmental information and neurotransmitters in HSCs mobilization.
Materials and methods:
This experimental study was performed on 15 healthy bone marrow donors. Samples from peripheral blood were taken at 9 o'clock in the morning and 9 o'clock at night, before the injection of G-CSF as control group, and at 9 o'clock in the morning and 9 o'clock at night on fourth day of the G-CSF injection, The total counts of leukocytes and CD34 + stem cells were performed on the samples by flow cytometry. Plasma levels of adrenaline and noradrenaline were measured by ELISA method analyzed by Paired T test.
Findings:
In this study, it was determined that total cell count, stem cell count (CD34 +)(p value: 0.03), and plasma levels of adrenaline(p value: 0.04) and noradrenaline(p value: 0.01) in the morning increased over night. Additionally, after receiving the G-CSF , adrenalin and norepinephrine levels are higher in the early hours after the onset of lighting than the night, and CD34 + cells count was higher in the morning than in the evening sush as control samples.
Conclusion:
Given that the number of stem cells and total WBC count in the morning was more than nights, In general, following the injection of G-CSF, the number of stem cells circulating with the same pattern shows a multiplier increase, It is suggested that the phenomenon of mobilization, like other biological processes of the body, is affected by circadian rhythms, Therefore, increased secretion of adrenaline and noradrenaline in the morning and the effect on ß2-adrenergic receptors in the bone marrow space resulted in increased mobilization and during the day, reducing the secretion of these neurotransmitters leads to contrary to this process and reduces mobilization in the final hours of the day and at night, In fact, G-CSF, along with other functional mechanisms for increasing the mobilization of stem cells to the peripheral blood, also uses this natural remedy for the body. These findings can be effective in enhancing approaches to improving mobilization with the help of the nervous system.
Key words:
Mobilization, adrenaline, noradrenaline, circadian rhythms, granulocyte-colony stimulating factors(G-CSF)